title: The Cambridge Anti-myopia Study: variables associated with myopia progression.
abstract: OBJECTIVE
  To identify variables associated with myopia progression and to identify any interaction between accommodative function, myopia progression, age, and treatment effect in the Cambridge Anti-Myopia Study.
  
  
  METHODS
  Contact lenses were used to improve static accommodation by altering ocular spherical aberration, and vision training was performed to improve dynamic accommodation. One hundred forty-two subjects, aged 14-21 years, were recruited who had a minimum of -0.75D of myopia. Subjects were assigned to contact lens treatment only, vision training only, contact lens treatment and vision training, or control group. Spherical aberration, lag of accommodation, accommodative convergence/accommodation (AC/A) ratio, accommodative facility, ocular biometry, and refractive error were measured at regular intervals throughout the 2-year trial.
  
  
  RESULTS
  Ninety-five subjects completed the 24-month trial period. There was no significant difference in myopia progression between the four treatment groups at 24 months. Age, lag of accommodation, and AC/A ratio were significantly associated with myopia progression. There was a significant treatment effect at 12 months in the contact lens treatment group in younger subjects, based on a median split, aged under 16.9 years (p = 0.005). This treatment effect was not maintained over the second year of the trial. Younger subjects experienced a greater reduction in lag of accommodation with the treatment contact lens at 3 months (p = 0.03), compared to older contact lens treatment and control groups. There was no interaction between AC/A ratio and contact lens treatment effect.
  
  
  CONCLUSIONS
  Age, lag of accommodation, and AC/A ratio were significantly associated with myopia progression. Although there was no significant treatment effect at 24 months, an interaction between age and contact lens treatment suggests younger subjects may be more amenable, at least in the short term, to alteration of the visual system using optical treatments.
authors.affiliation: *PhD Vision and Eye Research Unit (HP, PMA, RC, SR, BT), Postgraduate Medical Institute, Department of Vision and Hearing Sciences, Anglia Ruskin University, Cambridge, United Kingdom; Vision Cooperative Research Centre (HP, PMA, HR, RC, SR, BT, DJO), Sydney, Australia; Faculty of Life Sciences (HR), University of Manchester, Manchester, United Kingdom; School of Optometry (AS), National Institute of Ophthalmic Sciences, Academic arm of The Tun Hussein Onn National Eye Hospital, Malaysia; and Cardiff Metropolitan University, Cardiff (DJO), Wales, United Kingdom.
authors.forename: Holly
authors.initials: H
authors.lastname: Price
authors.forename: Peter M
authors.initials: PM
authors.lastname: Allen
authors.forename: Hema
authors.initials: H
authors.lastname: Radhakrishnan
authors.forename: Richard
authors.initials: R
authors.lastname: Calver
authors.forename: Sheila
authors.initials: S
authors.lastname: Rae
authors.forename: Baskar
authors.initials: B
authors.lastname: Theagarayan
authors.forename: Ananth
authors.initials: A
authors.lastname: Sailoganathan
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: O'Leary
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology; D000293:Adolescent; D001699:Biometry; D003263:Contact Lenses, Hydrophilic; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D009216:Myopia / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy*; D012029:Refraction, Ocular / Q000502:physiology; D055815:Young Adult